Adjustable surfing fin

ABSTRACT

According to some demonstrative embodiments of the present invention there is provided an apparatus for adjusting the flexibility of a fin of a waterborne vessel comprising at least one movable and/or rotatable component adapted to be positioned in one of at least two different positions, a first position and a second position, wherein when said component is positioned at said first position, said fin exhibits a first degree of flexibility, and when said component is positioned at said second position, said fin exhibits a second degree of flexibility, wherein said first degree of flexibility is greater then said second degree of flexibility.

FIELD OF THE INVENTION

The present invention relates to the field of mechanics and the mechanics of sport articles and specifically to a surfing fin having an adjustable flexibility.

BACKGROUND OF THE INVENTION

In many technical fields there is a need for use of elements which at times may require different degrees of stiffness and/or rigidity.

Airplanes may have an aerodynamic advantage if the wings of the aircraft may be lifted and/or flexed in an angle, for example, upon takeoff, descent or at extreme weather conditions.

Many watersports and aquatic activities use water-borne vessels having fins or keels beneath the surface of the vessel, adapted to allow steering of the vessel. Surfboards, windsurfing boards, and numerous other aquatic vessels use fins attached beneath the vessel in order to adjust or use the water flow beneath the vessel for steering and/or stability.

The characteristics of the fin, such as its level of flexibility, its size, its curves and its surface area all affect the water flow beneath the vessel and how the vessel reacts to steering operations.

Due to variability in the conditions of the high seas and different personal preferences of surfers, various fins have been developed in order to affect water flow differently, and thus to steer vessels differently and create different surfing experiences.

Surfboards manufactured today provide a base beneath the board, upon which a desired fin may be reversibly mounted. If a surfer desires a different fin, as a result of changing conditions or a different surfing style, the attached fin must be dismounted, and an alternative fin be mounted in its stead. Thus, a surfer wishing to change the flexibility or any other attribute of their fin must not only spend time and effort replacing a fin every time they wish to change their surfing experience, they must also carry around alternate/replacement fins. This may be true every time a surfer goes to surf, partially due to the inability to predict which fin they will need during the entirety of the surfing session.

Additionally, the surfer may not notice the unsuitability of their fin until reaching a certain distance from shore (e.g. where the waves are peaking), which would then require them to return to shore in order to replace said fin. Acquiring a set of fins for different surfing experiences may be expensive, as well as bulky when traveling.

U.S. Pat. No. 6,896,570 B1 describes a fin for a watersport board, which includes a substantially rigid core covered by a flexible core covering.

EP 0079113 A1 describes a fin for buoyant support suitable for a surf board, dinghy or wind sailing board or the like, formed of a resiliently flexible material such as solid urethane, reinforced with a stiffening insert which incorporates means for attachment to the surf board or the like.

What is common to the above inventions is that the fin allows for a fixed degree of flexibility and must be replaced every time a different flexibility is required.

U.S. Pat. No. 4,733,496 describes a novel fin for surfboards and watercraft that includes a pivoting rudder-like section that swings out when a turn is commenced, enhancing the maneuverability of the surfboard by reducing the resistance of the fin as it moves sideways through the water in a turn and by redirecting the water flow through the pivoting rudder section in the direction of the turn. Although said fin does provide left-right maneuverability, it does not provide the ability to change other aspects, such as flexibility of the fin.

U.S. Pat. No. 5,367,970 discloses a fin which is able, given the material that is used in its manufacturing process, to provide extra flexibility. This invention, however, relates to a fin manufactured by a specific process, and does not providing different levels of flexibility.

WO/2011/143695 describes a fin for a surf craft. Said fin is able, given the material that is used in its manufacturing process, to provide extra flexibility. This invention however does not providing different levels of flexibility.

U.S. Pat. No. 7,896,718 describes a keel or fin for a watercraft such as a surfboard that is conventional in shape with a major portion fixed to the board by peg and a minor, flexible, trailing portion fixed to the major portion. This invention however relates to a single adjustable fin which is comprised of an adjustable piece attached to it, giving it minimal flexibility.

SUMMARY OF THE INVENTION

In some demonstrative embodiments of the present invention there is provided an apparatus for adjusting the flexibility of an element comprising one or more movable parts adapted to be positioned in at least two different positions, a first position and a second position. According to some demonstrative embodiments, when said one or more movable parts is at the first position the element may exhibit a greater flexibility than when the one or more movable parts is at the second position.

According to some demonstrative embodiments, the apparatus may include one or more levers that may be positioned in at least two different positions, a first position and a second position, preferably, in a plurality of positions. According to some demonstrative embodiments, when said one or more levers is at the first position the element may exhibit a greater flexibility than when the one or more movable parts is at the second position. According to some embodiments, positioning the one or more levers in the first position provides for the greatest extent of rigidness of the element, whereas positioning the one or more levers in the second position provides for the greatest extent of rigidness of the element. According to some embodiments, positioning the one or more levers in one of a plurality of positions located between the first and the second position will provide a partial extent of rigidness or flexibility of the element, as explained in detail below.

In some demonstrative embodiments of the present invention there is provided an apparatus for adjusting the flexibility of an element comprising a disc comprising a plurality of rods and a plurality of slots; a screwing element; and wherein said disc may be rotated to various positions and reversibly locked in place via said plurality of slots and wherein rotating said disc to various position provides a different degree of flexibility to said element.

According to some demonstrative embodiments the element may be a wing of an aircraft.

According to some demonstrative embodiments the element may be a fin of a water-borne vessel.

According to some demonstrative embodiments the element may be a surfing fin.

In some demonstrative embodiments of the present invention there is provided a surfing fin adapted to fit into standard fittings of a waterborne vessel having variable flexibility comprising a disc adapted to fit into said fin and rotate within the fin around an axis; a screwing element adapted to center said disc and hold it in place while allowing for rotation of said disc; wherein said disc is adapted to rotate to a predefined set of stable positions, each providing a different degree of flexibility to said fin.

According to some demonstrative embodiments the fin may further comprise a cover plate adapted to fit over said disc and hold said disc in place while allowing rotation thereof.

According to some demonstrative embodiments the fin may further comprise a closing part adapted to fit over a bottom part of said fin and hold said disc in place while allowing rotation thereof.

According to some demonstrative embodiments the disc may comprise a plurality of rods adapted to provide a different degree of flexibility to said fin due to varying mechanical coupling between said rods and said fin.

According to some demonstrative embodiments the waterborne vessel may selected from the group consisting of: surfboard; kitesurf board; windsurf board; boogie board; paddle board; wave board; wake board; kayak; canoe; sailing boat; waterski, jetski.

According to some demonstrative embodiments the fin may include means for rotating said disc by hand.

According to some demonstrative embodiments the fin may include means for rotating said disc by means of a screw driver.

In some demonstrative embodiments of the present invention there is provided a wearable adjustment device adapted to enable the rotation of a disc contained within a surfing fin and to provide a different degree of flexibility to said surfing fin.

According to some demonstrative embodiments the wearable adjustment device may be a ring.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become fully understood from the detailed description given herein below and the accompanying drawings, which are given by way of illustration and example only, and thus not limiting in any way, wherein:

FIG. 1, is a schematic isometric view illustration of a disc in accordance with some demonstrative embodiments described herein.

FIG. 2 is a schematic illustration of an element including a disc, in accordance with some demonstrative embodiments described herein.

FIG. 3 is a schematic illustration of an element including a disc, in accordance with some demonstrative embodiments described herein.

FIG. 4 illustrates examples of discs in accordance with some demonstrative embodiments of the present invention.

FIG. 5 is a schematic exemplary illustration of a disc in accordance with some demonstrative embodiments described herein.

FIG. 6 is a schematic illustration of a screwing element in accordance with some demonstrative embodiments described herein.

FIG. 7 is a side-view illustration of a surfing fin according to some demonstrative embodiments described herein.

FIG. 8, illustrates an exploded view of a surfing fin, in accordance with some demonstrative embodiments described herein.

FIG. 9 is a schematic illustration of a surfing fin in accordance with some demonstrative embodiments described herein.

FIG. 10 is a schematic illustration of a closing part in accordance with some demonstrative embodiments described herein.

FIG. 11 is a schematic cross-section side view illustration of an exemplary fin, in accordance with some demonstrative embodiments described herein.

FIG. 12 illustrates an exemplary adjustably flexible fin in accordance with some demonstrative embodiments described herein.

FIG. 13 is a schematic side view illustration of an adjustably flexible surfing fin, in accordance with some demonstrative embodiments.

FIG. 14 is a schematic isometric cross section view illustration of adjustably flexible surfing fin, in accordance with some demonstrative embodiments described herein.

FIG. 15 is a schematic side view illustration of a flexible fin and inner part, in accordance with some demonstrative embodiments described herein.

FIG. 16 is a schematic side view illustration of a flexible fin, in accordance with some demonstrative embodiments described herein.

FIG. 17 is a schematic illustration of an adjustably flexible fin, in accordance with some demonstrative embodiments described herein.

FIGS. 18-20 are schematic illustrations of a wearable ring including a screw driver, in accordance with some demonstrative embodiments described herein.

FIG. 21 illustrates an exemplary adjustably flexible fin in accordance with some demonstrative embodiments described herein.

FIG. 22 illustrates an exemplary adjustably flexible fin in accordance with some demonstrative embodiments described herein.

FIG. 23 illustrates an exemplary apparatus for a flexible fin in accordance with some demonstrative embodiments described herein.

DETAILED DESCRIPTION OF THE INVENTION

In some demonstrative embodiments, there is provided an apparatus for adjusting the flexibility of a device, element or surface comprising the apparatus.

According to some demonstrative embodiments the apparatus may be a manually adjustable apparatus, wherein the apparatus may have at least two positions wherein at each position of the apparatus controls the flexibility of the device, element or surface comprising the apparatus.

In some demonstrative embodiments of the present invention there is provided an apparatus for adjusting the flexibility of an element comprising one or more internal movable parts adapted to be positioned in at least two different positions, a first position and a second position. According to some demonstrative embodiments, when said one or more movable parts is at the first position the element may exhibit a greater flexibility than when the one or more movable parts is at the second position.

According to some demonstrative embodiments, there is provided an apparatus for adjusting the flexibility of an element comprising one or more movable rods and/or levers adapted to be positioned in at least two different positions, a first position and a second position. According to some demonstrative embodiments, when said one or more movable parts is at the first position the element may exhibit a greater flexibility than when the one or more movable parts is at the second position.

According to some demonstrative embodiments, there is provided an apparatus for adjusting the flexibility of an element comprising one or more discs adapted to be rotated to at least two different positions, a first position and a second position.

According to some demonstrative embodiments, when said disc is at the first position the element may exhibit a greater flexibility than when the disc is at the second position.

The device, element or surface as referred to herein may include any type of material that may be used in a mechanical, aeronautical, aquatic or any suitable field.

According to some demonstrative embodiments, the device, element or surface may be a wing and/or tail of an aircraft, for example, when comprising the apparatus of the present invention, the wing and/or tail may be bent or flexed towards a desired direction. This may be extremely beneficial as the design and analysis of the wings of aircraft is one of the principal applications of the science of aerodynamics. The properties of the airflow around any moving object can—in principle—be found by solving the Navier-Stokes equations of fluid dynamics.

For a wing to produce “lift”, it must be oriented at a suitable angle of attack relative to the flow of air past the wing. When this occurs the wing deflects the airflow downwards, “turning” the air as it passes the wing. Since the wing exerts a force on the air to change its direction, the air must exert a force on the wing, equal in size but opposite in direction. This force manifests itself as differing air pressures at different points on the surface of the wing.

A region of lower-than-normal air pressure is generated over the top surface of the wing, with a higher pressure existing on the bottom of the wing. These air pressure differences can be either measured directly using instrumentation, or they can be calculated from the airspeed distribution using basic physical principles, including Bernoulli's Principle which relates changes in air speed to changes in air pressure.

The lower air pressure on the top of the wing generates a smaller downward force on the top of the wing than the upward force generated by the higher air pressure on the bottom of the wing. Hence, a net upward force acts on the wing. This force is called the “lift” generated by the wing.

The different velocities of the air passing by the wing, the air pressure differences, the change in direction of the airflow, and the lift on the wing are intrinsically one phenomenon. It is, therefore, possible to calculate lift from any of the other three. For example, the lift can be calculated from the pressure differences, or from different velocities of the air above and below the wing, or from the total momentum change of the deflected air. There are other approaches in fluid dynamics to solving these problems. All of these approaches will result in the same answers if done correctly.

Usually, aircraft wings have various devices, such as flaps or slats that the pilot uses to modify the shape and surface area of the wing to change its operating characteristics in flight. In 1948, Francis Rogallo invented the fully limp flexible wing, which ushered new possibilities for aircraft. Near in time, Domina Jalbert invented flexible un-sparred ram-air airfoiled thick wings. These two branches of wings have been since extensively studied and applied in new branches of aircraft, especially altering the personal recreational aviation landscape.

According to some embodiments, the apparatus of the present invention, when applied and/or incorporated into the wings and/or tail of an aircraft may facilitate in the alleviation and/or descent of the aircraft or stabilize the aircraft in extreme weather conditions, e.g., stormy or windy weather.

According to some preferred embodiments of the present invention, the apparatus described herein may have advantageous characteristics especially when applied to water-borne vessels, for example, a water-borne vessel may be selected from the group consisting of: surfboard; kitesurf board; windsurf board; boogie board; paddle board; wave board; wake board; kayak; canoe; Stand Up Paddleboard (SUP); sailing boat; waterski, jetski and the like.

According to some preferred embodiments of the present invention, the apparatus described herein may also be used to be applied to other sporting equipment like skateboards, snowboards and the like.

According to more preferred embodiments of the present invention, the apparatus described herein may be implemented and/or incorporated in a surfing fin.

A preferred embodiment of this invention consists of a special ‘variable rigidity’ and/or ‘variable flexibility’ fin or keel, attached at its base to a surf board, which allows a surfer to quickly and easily adjust the flexibility and/or other features of the fin by use of the adjustable apparatus. As will be clear to one skilled in the art, the device allows for a versatile surfing experience. It allows the surfer to be able to adjust the flexibility of the fin without the need to return to shore. Furthermore, it saves the cost of a full set of fins, and is easier to carry and travel with than a full set of fins.

As also referred to hereinabove, the apparatus of the present invention may be very useful in the application of fluid dynamics which includes aerodynamics (the study of air and other gases in motion) and hydrodynamics (the study of liquids in motion).

Surfing fins can provide lateral lift opposed to the water and stabilize the trajectory of a surf board, allowing the surfer to control direction by varying their side-to-side weight distribution.

Surfboard fins may be arrayed in various number and configuration, and many different shapes, sizes, and materials are and have been made and used.

Both a skeg and “rail fins” stabilize the motion of the surfboard. They also contribute to the desired effect of converting the (kinetic energy) push of the sloped wave face combined with the riders mass on the sloped wave face (potential energy) into redirected energy—lift (lift (physics))—the surfer deflects his surfboard and fins off the water of the wave face (and/or vice-versa) to make forward progress across the wave face, or “down the line,” that is, parallel to the wave crest and beach—riding parallel to the crest (perpendicular to the pull of gravity down the wave's slope) in this way is known as “trimming.” Lift (aka “drive”) from the board and its fin(s) is what enables all maneuvers in surfing.

A “skeg” (an upright, streamlined, often raked keel) typically denotes one centrally-mounted stabilizer foil mounted perpendicularly to the riding surface, at the rear of the surfboard.

Smaller surfboard fins mounted near the edge (or “rail”) of the surfboard are known as “rail fins” and are seen in multi-fin arrangements (often in combination with a similarly-sized central fin further back on the board). Rail fins enable high-performance surfing, and are most often “single-foiled,” with one flat side and one “foiled” side, as seen on an airfoil, for greater lift.

A fin configuration with fins near the edge of the board stabilizes and contributes lift during turning maneuvers, which contributes to the board's ability to “hold” during turning maneuvers. Rail fins are often seen in addition to a central fin, but can be used without a central fin as well. Some of the most popular multi-fin configurations use two rail fins (a “twin-fin”), two rail fins plus a similar-sized central fin mounted further back (e.g. a “Thruster”), or four fins (a “quad”). Rail fins are more or less engaged by the rider's heel and toes as they lean in the desired direction of their turn.

As the rider does so, an “inside” rail fin sinks deeper and its angle of attack is increased, as is its lift-induced drag. Rail fins also add lift (known as “drive”) in trim and with greater holding ability, enable steeper wave faces to be ridden and higher speed “down the line.”

In Windsurfing, a derivative of traditional surfing, skegs are also often used as a central stabilizing fin (hydrofoil) located at the rear of the board. A windsurfer's skeg also has the effect of producing lift, which allows the rider to direct the craft laterally against the lift the sail (itself an airfoil) produces. The skeg has undergone numerous phases of development and, as with other foils, its design is determined by the balance of the pressures it experiences in use, including lift, drag (physics), ventilation and stall (flight).

It is to be understood that the term “Flexibility” and/or “Stiffness” as used herein relates to the rigidity of an object, i.e., the extent to which it resists deformation in response to an applied force. The more flexible an object is, the less stiff it is.

The stiffness, k, of a body is a measure of the resistance offered by an elastic body to deformation. For an elastic body with a single degree of freedom (for example, stretching or compression of a rod), the stiffness is defined as

$k = \frac{F}{\delta}$

where,

F is the force applied on the body

δ is the displacement produced by the force along the same degree of freedom (for instance, the degree of bent of a flexible surfing fin)

In the International System of Units, stiffness is typically measured in newtons per metre. In Imperial units, stiffness is typically measured in pounds (lbs) per inch.

Deflection is the degree to which an element is displaced under a load. It may refer to an angle or a distance.

The deflection distance of a member under a load is directly related to the slope of the deflected shape of the member under that load and can be calculated by integrating the function that mathematically describes the slope of the member under that load.

Deflection can be calculated by standard formula, or by methods such as virtual work, direct integration, Castigliano's method, Macaulay's method or the direct stiffness method, amongst others.

Flexibility is also directly linked to the Flexural Modulus. Flexural Modulus of a tested specimen being bended between three points is measured by the ratio of the strain observed on the stress applied on it.

The International Standard unit of Flexural Modulus is the pascal (Pa or N/m² or m-l.kg.s⁻²). The practical units used in plastics are megapascals (MPa or N/mm²) or gigapascals (GPa or kN/mm²). In the US customary units, it is expressed as pounds (force) per square inch (psi).

The higher the Flexural Modulus, the stiffer the material. The lower the Flexural Modulus, the more flexible it is.

Most commonly used standards to measure Flexural Modulus are ASTM D790 and ISO 178.

According to some demonstrative embodiments there is provided an apparatus for adjusting a degree of flexibility of a surfing fin, wherein the apparatus includes at least one movable part configured to be moved from a first position to at least a second position, wherein upon moving the part from the first position to the at least a second position the degree flexibility of the fin may be changed, for example from 0.001 GPa to 30 GPa.

For example, there is provided a surfing fin (also referred to herein as an “adjustably flexible surfing fin”) comprising the apparatus of the present invention which may be set at a first position (also referred to herein as “base position”) wherein the surfing fin is at a relatively rigid state, i.e., a standard amount of force applied to the fin will not cause the deflection or bending of the fin. It is to be understood that the term standard amount of force relates to a force applied to a surfing fin by sea waves or underwater currents applying force onto the fin.

When the apparatus of the present invention is set at a second position the surfing fin is at a relatively flexible state, i.e., a standard amount of force applied to the fin will cause the deflection or bending of the fin, for example, bending up to 90° to either side, in relation to the basic position of the fin.

According to some demonstrative embodiments, the apparatus may be configured to be set to more than two different positions, thereby enabling various degrees of flexibility to the surfing fin, e.g., as explained in detail below.

The terms “multi” and/or “plurality” as used herein include, for example, “multiple” or “two or more”. For example, “multi compartment” includes two or more compartments.

According to some demonstrative embodiments there is provided a surfing board comprising the adjustably flexible surfing fin of the present invention, wherein the surfing board may be suitable for use in various sea conditions, for example, when the waves are high and/or when the waves are low.

For example, a user of a surfing board according to the present invention, may adjust the adjustably flexible surfing fin to be at a rigid state for specific sea conditions, for example, when the waves are high, and according to other demonstrative embodiments, the user may adjust the adjustably flexible surfing fin to be at a flexible state for specific sea conditions, for example, when the waves are low.

A relatively rigid fin enables the user to have more stability when the waves are high, e.g., by having a better “grasp” of the board in the waters. Alternatively, relatively flexible fin enables the user to have more “freedom” when the waves are low, e.g., by having better maneuverability of the board in the waters.

According to some demonstrative embodiments, when the surfing fin is at a rigid state the deflection degree from a base position will not be greater than ±5 degrees.

However, when the fin is at the maximum flexible state the deflection degree from the base position may reach up to ±90 degrees. Preferably, the deflection degree of the fin should be no more than ±45 degrees.

In some demonstrative embodiments of the present invention there is provided an apparatus for adjusting the flexibility of an element comprising one or more movable parts adapted to be positioned in at least two different positions, a first position and a second position. According to some demonstrative embodiments, when said one or more movable parts is at the first position the element may exhibit a greater flexibility than when the one or more movable parts is at the second position.

According to some demonstrative embodiments, the apparatus may include one or more levers that may be positioned in at least two different positions, a first position and a second position, preferably, in a plurality of positions. According to some demonstrative embodiments, when said one or more levers is at the first position the element may exhibit a greater flexibility than when the one or more movable parts is at the second position. According to some embodiments, positioning the one or more levers in the first position provides for the greatest extent of rigidness of the element, whereas positioning the one or more levers in the second position provides for the greatest extent of rigidness of the element. According to some embodiments, positioning the one or more levers in one of a plurality of positions located between the first and the second position will provide a partial extent of rigidness or flexibility of the element, as explained in detail below.

The term “lever” as used herein may refer for example to any suitable movable part or component, the position of which may be controlled by a user of the apparatus of the present invention. According to some demonstrative embodiments the lever may be made of a rigid material, including, for example, rigid plastic, metal or metal alloys, wood and the like. According to other embodiments, the lever may be made of flexible or semi-flexible material to provide for greater flexibility of the fin upon operation of the apparatus, including, for example, flexible plastic, rubber and the like.

According to some demonstrative embodiments, there is provided an element including the apparatus which may include a disc having a plurality (two or more) of rods, wherein upon turning the disc from a first position to at least a second position the flexibility of the element may vary, for example, as explained in detail below.

According to some demonstrative embodiments the disc may be made of any suitable material that may enable the bending of the disc in an opposite direction to the direction of alignment of the rods, and may enable stiffness of the disc along the direction of alignment of the rods. Examples of such suitable materials may include Steel, Iron, Aluminum, copper, titanium, zinc, carbon fibers, silicones, rubber, wood, plastics, composite materials fibers, composite materials and the like.

According to some demonstrative embodiments, the surfing fin may be made of any suitable material including polyurethane, polystyrene foam, fiberglass, polyester, epoxy resin, kevlar fiber, carbon fibers, silicones, rubber, wood, plastic or any combination thereof.

According to some demonstrative embodiments, the use of the surfing board including one or more adjustably flexible surfing fin(s) may enable a user of the board, i.e., a surfer, to control the degree of flexibility of the surfing fin and/or adjust the flexibility of the fin in accordance with the conditions of the sea, i.e., according to the height of the waves, wind conditions, physical state of the surfer or personal preference.

Use of the adjustably flexible surfing fin may obviate the need to swim back to shore and replace one or more fins of the surfing board.

According to some demonstrative embodiments, a user of a surfing fin described herein may change the degree of flexibility of the fin manually by rotating the disc within the surfing fin.

According to some other demonstrative embodiments of the present invention, there is provided a wearable adjustment device, configured to enable a user of the surfing fin of the present invention to adjust the degree of flexibility of the surfing fin.

According to some embodiments, the term “wearable adjustment device” may refer to any suitable article that may placed upon the surfer's body and/or to be carried with the surfer into the waters when surfing, including, for example, attachments to the cloths of the surfer, jewelry, such as rings, necklaces, wrist bands, bracelets and the like.

According to some demonstrative embodiments, there is provided an apparatus for adjusting the flexibility of a fin of a waterborne vessel comprising at least one movable and/or rotatable component adapted to be positioned in one of at least two different positions, a first position and a second position, wherein when said component is positioned at said first position, said fin exhibits a first degree of flexibility, for example, 0.001 GPa and when said component is positioned at said second position, said fin exhibits a second degree of flexibility, for example 30 GPa, wherein said first degree of flexibility is greater then said second degree of flexibility.

According to some demonstrative embodiments, the waterborne vessel may be selected from the group consisting of: surfboard; kitesurf board; windsurf board; boogie board; paddle board; wave board; wake board; kayak; canoe; sailing boat; waterski, jetski.

According to some demonstrative embodiments, the component may comprise a disc comprising a plurality of rods and a plurality of slots; a screwing element; and wherein the disc may be rotated to various positions and reversibly locked in place via said plurality of slots and wherein rotating said disc to various positions provides a different degree of flexibility to said fin.

According to some embodiments the apparatus may include means for rotating said disc by hand.

According to some other embodiments of the present invention the apparatus may include means for rotating said disc by means of a screw driver.

According to some demonstrative embodiments the component may comprise a movable lever adapted to be positioned in one of at least two different positions, a first horizontal position and a second vertical position, wherein when the component is positioned at the first horizontal position, the fin may exhibit a first degree of flexibility, and when the component is positioned at the second vertical position, the fin may exhibit a second degree of flexibility, wherein the first degree of flexibility is greater then the second degree of flexibility

According to some demonstrative embodiments, there is provided a wearable adjustment device adapted to enable the rotation of a disc contained within a fin and to provide a different degree of flexibility to said fin.

According to some demonstrative embodiments, device may be a ring, as described in detail herein.

According to some demonstrative embodiments of the present invention, there is provided herein an apparatus for controlling the flexibility of a surfing fin, wherein said apparatus comprises at least one movable and/or rotatable component adapted to be positioned in one of at least two different positions, a first position—causing the surfing fin to have a flexibility ranging from about 0.001 GPa to 5 GPa, (also referred to herein as “flexible fin mode”) and a second position—causing the surfing fin to have a flexibility ranging from 1 GPa to 30 GPa (also referred to herein as “rigid fin mode”).

According to some demonstrative embodiments, the apparatus may be positioned in a plurality of different position (also referred to herein as “intermediate positions”) ranging from the first position to the second position, thereby providing for various controllable degrees of flexibility of the surfing fin.

EXAMPLES

The following are examples of various flexibility characteristics of surfing fins corresponding to various position of the apparatus described herein in accordance with some demonstrative embodiments:

Flexibility Value (GPa) 1^(st) 2^(nd) position position (flexible 1^(st) 2^(nd) 3^(rd) 4^(th) (rigid fin intermediate intermediate intermediate intermediate fin Fin composition mode) position position position position mode) Polyvinyl Chloride 4.5 5 5.5 6 6.5 7 20% glass fiber Polyvinyl Chloride 0.001 0.05 0.1 0.5 1.2 1.8 plasticized Polyvinyl 2.1 2.4 2.7 3.0 3.3 3.5 Chloride rigid Polyetheretherketone 13 14 15 16.5 18 19 30% carbon fiber

Reference is now made to FIG. 1, which is a schematic isometric view illustration of a disc 100 in accordance with some demonstrative embodiments described herein.

According to some demonstrative embodiments, the apparatus of the present invention may include at least one disc 100 and may be implemented in an element and/or a device to control the flexibility of the element and/or device.

As shown in FIG. 1, disc 100 may include at least one rod 102 which enables disc 100 to bend in the direction opposite to the direction of alignment of rod(s) 102 and stay rigid in the direction conforming with the direction of alignment of rod(s) 102, as shown in FIGS. 2A-2B and 3A-3C.

According to some demonstrative embodiments, rods 102 may have indentations along each rod (not shown in the figure) adapted to contain and/or absorb salt and/or sand that might penetrate the surfing fin and potentially interrupt the smooth rotation of disc 100.

Reference is now made to FIG. 2 which illustrates an element 200 including disc 100, in accordance with some demonstrative embodiments described herein.

FIG. 2A is a top plane view of element 200 and FIG. 2B is an isometric view of element 200.

As shown in FIG. 2, according to some demonstrative embodiments, disc 100 may be at a first position, wherein element 200 is essentially rigid, i.e., cannot be bent.

According to some embodiments, due to the rigidity of rods 102 (FIG. 1) disc 100 prevent bending element 100.

Reference is now made to FIG. 3 which illustrates element 200 including disc 100, in accordance with some demonstrative embodiments described herein.

FIG. 3A is a top plane view of element 200 and FIG. 3B is an isometric view of element 200 and FIG. 3C is a side view of element 200.

As shown in FIG. 3, according to some demonstrative embodiments, disc 100 may be at a second position, wherein element 200 is essentially flexible, i.e., can be bent.

According to some demonstrative embodiments, disc 100 at the second position is rotated 90 degrees in comparison to the first position depicted in FIG. 2.

According to these embodiments, by rotating disc 100 the degree of flexibility of element 200 is altered. From the first position of disc 100, as depicted in FIG. 2, wherein element 200 is at the maximum rigidity and up to the second position depicted in FIG. 3, wherein element 200 is at the maximum flexibility.

Reference is now made to FIG. 4 which illustrates examples of discs in accordance with some demonstrative embodiments of the present invention.

According to some demonstrative embodiments, disc 100 (FIG. 1) may include any suitable form, for example, as exemplified by the discs depicted in FIG. 4.

FIG. 4A illustrates an isometric view of a disc having diagonally formed indentations.

FIG. 4B illustrates an isometric view of a disc having a relatively small, i.e., shallow, but numerous indentations.

FIG. 4C illustrates an isometric view of a disc having square indentations. The disc depicted in FIG. 4C is preferable, as the square indentations demonstrate a stable disc when a rigid position is desired and substantial bending spectrum when a flexible position is desired.

According to some demonstrative embodiments, the use of of a specific disc may be determined according to the material of which the surfing fin is made of and/or sea conditions.

For example, if the surfing fin is transparent, a better looking disc may be used, e.g., the disc of FIG. 4A. Another example, if the sea is stormy and the waves are high, the disc of FIG. 4C may be preferable as it may provide for better flexibility characteristics to the surfing fin.

Reference is now made to FIG. 5 which is a schematic exemplary illustration of a disc 100 (FIG. 1) in accordance with some demonstrative embodiments described herein.

FIG. 5A is an isometric view of disc 100, FIG. 5B is a front view and FIG. 5C is a side view illustration of disc 100.

Disc 100 may include a plurality of rods 102 and a central rod 504. According to some embodiments, rod 504 may be thicker than other rods of disc 100, e.g., in order to provide stability and/or stiffness to disc 100. According to some embodiments in the center of rod 504 there may opening 506 configured to encompass at least one screwing element (see for example as detailed with regard to FIG. 6 below).

Disc 100 may also include a plurality of slots 502 intended to stop the rotation of disc 100. According to some embodiments, when disc 100 is incorporated into an element, e.g., a surfing fin, the element will include one or more bumps configured to fit into slot 502. Disc 100 may be rotated to different position (thereby determining the flexibility of the element) wherein the disc 100 is stopped at each position when each slot 502 reaches the bump.

Reference is now made to FIG. 6 which illustrates a screwing element 600 in accordance with some demonstrative embodiments described herein.

According to some demonstrative embodiments, screwing element 600 may be inserted in opening 506 (FIG. 5) and enable the rotation of disc 100.

According to some demonstrative embodiments, rotating disc 100, e.g., via screwing element 600, changes the position of the rods of disc 100 and accordingly the flexibility of an element comprising disc 100.

According to some demonstrative embodiments of the present invention, screwing element 600 may include any suitable type of screw drive (head indentations), including for example, Slot (regular), Phillips, Pozidriv (SupaDriv) PZ, Square, Robertson (square), Hex, Hex socket (Allen), Security hex socket (pin-in-hex-socket), Torx (T & TX), Security Torx (TR), Tri-Wing, Torq-set, Spanner head, Double-square, Triple square (XZN), Polydrive, One-way, Spline drive, Double hex, Bristol, Pentalobular and the like.

According to some demonstrative embodiments, the user of a surf board including the apparatus described herein may have at least one tool to enable to rotation of disc 100 via screwing element 600. For example, the user may have at least one ring including a screw driver to operate screwing element 600, e.g., as described below with regard to FIGS. 24-26.

Reference is now made to FIG. 7, which is a side-view illustration of a surfing fin according to some demonstrative embodiments described herein.

The port surface of the fin has indentations and protrusions 702 which fit the disc 100, allowing the fin to rotate through a discrete set of reversibly fixed positions.

Protrusions and indentations 702 fit into corresponding indentations and protrusions of the disc 100 and hold the disc securely into place in a discrete set of positions, allowing for different flexibilities. According to some embodiments, slots 502 fit the protrusion of spring 704, defining a discrete set of stable positions as will be clear to one skilled in the art.

Reference is now made to FIG. 8, which illustrates an exploded view of a surfing fin 700 (FIG. 7), in accordance with some demonstrative embodiments described herein.

The mechanism depicted in FIG. 8 consists of a disc 100 that fits into fin 700. Disc 100 may be rotated such that protrusions 702 on the base part of fin 700 align with different parts of disc 100, leading to different degrees of support to the fin and differing subsequent flexibility of the fin. A spring-like pin 704 reversibly locks disc 100 into place. Screw element 600 holds disc 100 in place while allowing rotation of disc 100 to various positions. A cover plate 800 fits over disc 100 and holds said disc in place while allowing it to rotate about screwing element 600.

According to some demonstrative embodiments, the surfer may adjust the flexibility of the fin by inserting an object such as a screwdriver or wrench into the screwing element, and turning clockwise or counter-clockwise. This will cause disc 100 and its protrusions to rotate and lock into matching indentations 702 on the fin part 700. Each locked position provides the fin with a different level of flexibility.

In some demonstrative embodiments, as disc 100 rotates within the fin, the protruding pieces move, and mate with the indentations on the disc. Due to the varying degree of coupling between disc and fin, different flexibilities are achieved and as a result a different surfing experience is achieved.

According to some demonstrative embodiments, the apparatus may be mounted on a surf board, windsurfing board, and other aquatic vessels which use fins or keels to manipulate the water flow beneath the vessel and thus facilitate maneuvering of the vessel itself.

FIG. 8 shows disc 100 which is inserted between the base part of fin 700 and cover plate 800 creating a rotatable apparatus within the fin. Disc 100 has elements which fit in corresponding circular indentations in fin 700, to lock the dis 0063 in place. In addition, a hole 802 may be visible, within which an object may be inserted to adjust the disc which turns on a bearing or screwing element 600. According to some demonstrative embodiments, hole 802 may also be used to show the degree of flexibility of fin 700, for example, disc 100 may include one or more markings, e.g., 1, 2, 3, 4, 5 etc., wherein upon rotating disc 100 within fin 700 the degree of may be visible to the user via hole 802. A spring 704 may be used to force the disc into a set of stable positions.

Reference is now made to FIGS. 9A and 9B which illustrate a surfing fin 900 in accordance with some demonstrative embodiments described herein.

FIG. 9A is a cross section side view of fin 900 and FIG. 9B is an isometric cross section view of fin 900.

Fin 900 may include disc 100 (FIG. 1), but unlike fin 700 (FIG. 7), Fin 900 has one or more opening in the bottom portion of fin 900 to enable the insertion of disc 100.

According to some demonstrative embodiments, fin 900 may include a closing part 902 configured to force disc 100 into a set of stable positions.

Reference is now made to FIG. 10 which is a side view illustration of closing part 902 in accordance with some demonstrative embodiments described herein.

As shown in FIG. 10, closing part 902 is to close the bottom opening of fin 900 (FIG. 9) after disc 100 is inserted into fin 900.

According to some demonstrative embodiments, closing part 902 may include at least one bump 1004, designed to fit the one or more slots 502 (FIG. 5) of disc 100. Bump 1004 may have some flexibility due to hole 1006 which enables pulling back bump 1004 when disc 100 is rotated within fin 900.

Reference is now made to FIG. 11, which illustrates a cross-section side view of an exemplary fin 1100, in accordance with some demonstrative embodiments described herein.

As shown in FIG. 11, fin 1100 may include a plurality of discs to provide additional flexibility sections to fin 1100. According to some embodiments, the more discs are inserted into a surfing fin, more flexible points are created and the overall flexibility may be greater in comparison to the incorporation of a single disc.

As shown in FIG. 11, the discs may be connected to one another, e.g., wherein by rotating one of the disc the remaining discs may also be rotated. For example, at least one of the discs may include a cog-wheel to provide control over one or more of the other discs of fin 1100.

Reference is now made to FIG. 12, which illustrates an exemplary adjustably flexible fin. FIG. 12A illustrates a side view of the exemplary adjustably flexible fin and FIG. 12B is an isometric view of the exemplary adjustably flexible fin.

According to some demonstrative embodiments, the exemplary adjustably flexible fin may include a disc, e.g., disc 100 (FIG. 1), and a plurality of different materials to provide different flexibility to separate parts of the exemplary adjustably flexible fin.

According to some embodiments, the exemplary adjustably flexible fin may have a top portion 1202, a bottom portion 1204 and a middle portion 1206. According to some embodiments, the exemplary adjustably flexible fin may include more than three different parts.

In some embodiments, each of said portions may be made of a different material.

For example, portions 1202 and 1204 may be made of rigid and/or stiff material and portion 1206 may be made of a flexible material.

According to other embodiments, portions 1202 and 1204 may be made of flexible material and portion 1206 may be made of a rigid and/or stiff material.

Examples of rigid/stiff materials may include but not limited to Steel, Iron, Aluminum, copper, titanium, zinc, carbon fibers, wood, plastics, composite materials fibers, composite materials, polystyrene foam, fiberglass, polyester, epoxy resin, carbon fibers, silicones, rubber, wood, plastic or any combination thereof.

Examples of flexible materials may include Aluminum, silicones, rubber, flexible composite materials fibers, composite materials, polyurethane, flexible polystyrene foam, fiberglass, polyester, epoxy resin, kevlar fiber, carbon fibers, silicones, rubber, flexible wood, plastic or any combination thereof.

Reference is now made to FIG. 13 which illustrates a side view of an adjustably flexible surfing fin 1300, in accordance with some demonstrative embodiments.

As shown in FIG. 13, fin 1300 may include a plurality of slots 1302. According to some demonstrative embodiments, fin 1300 may include at least one inner element (not shown in the figure) which may include a plurality of bumps, wherein when the bumps are aligned with slots 1302 a higher degree of flexibility of fin 1300 is resulted in comparison to a lower degree of flexibility when the bumps are not aligned with slots 1302.

FIG. 14 illustrates an isometric cross section view of adjustably flexible surfing fin 1400, in accordance with some demonstrative embodiments described herein.

As shown in FIG. 14, fin 1400 may include a plurality of bumps 1402. According to some demonstrative embodiments, fin 1400 may include at least one inner element 1404 which may include a plurality of slots 1406, wherein when the bumps 1402 are aligned with slots 1406 a higher degree of flexibility of fin 1400 is resulted in comparison to a lower degree of flexibility when bumps 1402 are not aligned with slots 1406.

As shown in FIG. 14 the size of bumps 1402 and/or slots 1406 may vary, for example, in order to provide variable degrees of flexibility. The user of fin 1400 may control the degree of flexibility of fin 1400 by pushing in or pulling out element 1404 within fin 1400.

Reference is now made to FIG. 15, which illustrates a side view of flexible fin 1500 and inner part 1502, in accordance with some demonstrative embodiments described herein.

As shown in FIG. 15, fin 1500 may include a plurality of bumps 1504. According to some demonstrative embodiments, inner part 1502 which may include a plurality of slots 1506.

Inner part 1502 may be inserted into fin 1500 through one or more openings and may be pushed in or pulled out to various positions using lever 1508.

According to some embodiments, when the bumps 1504 are aligned with slots 1506 a higher degree of flexibility of fin 1500 is resulted in comparison to a lower degree of flexibility when bumps 1504 are not aligned with slots 1506. A partial alignment of bumps 1504 and slots 1506 will result in partial alignment.

Reference is made to FIG. 16 which illustrates a side view of flexible fin 1600, in accordance with some demonstrative embodiments described herein.

As shown in FIG. 16, fin 1600 may include slit 1602, e.g., to enable a flexible movement of fin 1600.

According to some demonstrative embodiments, fin 1600 may include one or more movable elements positioned within slit 1602 to enable the adjustment of the degree of flexibility of fin 1600.

Slit 1602 may be positioned along fin 1600 wherein a relatively small portion 1604 of fin 1600 is maintained in tack. According to some embodiments, the one or more movable elements may be positioned along slit 1602 in varying positions. Adjusting the one or more movable elements to a position close to portion 1604 will result in a higher degree of flexibility of fin 1600 in comparison to a position far from portion 1604, which will result in a lower degree of flexibility of fin 1600.

According to some demonstrative embodiments, slit 1602 may cause fin 1600 to be more prone to breakage. In some embodiments, one or more reinforcement element may be implemented in fin 1600 to prevent such breakage (not shown in the figure).

For example, a “U-Shaped” metal element may be implemented surrounding slit 1602 to provide stronger reinforcement to fin 1600.

Reference is now made to FIG. 17, which is a schematic illustration of an adjustably flexible fin 1700, wherein FIG. 17A is a side view cross section illustration and FIG. 17B is an isometric cross section illustration.

Fin 1700 may include one or more slits 1704, providing a flexible point to fin 1700.

According to some demonstrative embodiments, fin 1700 may include a disc 1702, may be rotated to expose different lengths of slit 1704 and accordingly enable the adjustment of various degrees of flexibility of fin 1700.

According to some embodiments, disc 1702 may include openings 1706 having different lengths and/or sizes. When disc 1702 is rotated to a position exposing a short portion of slit 1704, a lower degree of flexibility of fin 1700 is resulted in comparison to a situation wherein disc 1702 is rotated to a position exposing a longer portion of slit 1704, whereas a higher degree of flexibility of fin 1700 is resulted, e.g., because fin 1700 may be bent more.

Reference is now made to FIGS. 18-20 which illustrate a wearable ring including a screw driver to enable the user of a surfing fin of the present invention to adjust the flexibility of the fin, in accordance with some demonstrative embodiments described herein.

FIG. 18 is an isometric view of a ring 1800 which includes a screw driver 1802 and may be wore by a surfer and enable the surfer to adjust the degree of flexibility of the surfing fin of the present invention in the water, without needing to get back to shore and/or without requiring from the surfer to carry special tools.

According to some embodiments, ring 1800 may include a protective base 1804 for screw driver 1802.

According to some demonstrative embodiments, the ring may have at least a first “close” position and a second “open” position.

FIG. 18 illustrates the ring in a “close” position, wherein screw driver 1802 is not exposed, and is covered by protective base 1804. The “open” position is depicted in FIG. 20.

FIG. 19 is an isometric view of the two parts of ring 1800 (FIG. 18). According to some embodiments, ring 1800 may include a base part 1902 including screw driver 1802 and a covering part 1900 including protective base 1804.

According to some embodiments, covering part 1900 may slide along base part 1902 and enable a user of ring 1800 to change the position of the ring from “open” to “close” and vice versa.

FIG. 20 is an isometric view of ring 1800 (FIG. 18). FIG. 20 illustrates the ring in an “open” position, wherein screw driver 1802 is exposed, and is not covered by protective base 1804.

Reference is now made to FIG. 21, which illustrates an exemplary adjustably flexible fin 2100. FIG. 21A illustrates a side view of the exemplary adjustably flexible fin 2100 and FIG. 21B is an isometric view of the exemplary adjustably flexible fin 2100.

According to some demonstrative embodiments, fin 2100 may include a cavity 2104, for example in the base portion of fin 2100. Cavity 2104 may comprise between 10%-90% of the overall size of fin 2100.

In some demonstrative embodiments, cavity 2104 provides for a degree of flexibility to fin 2100 because of the hollow interior of fin 2100, e.g., in comparison to a non-hollow surfing fin.

According to some embodiments, cavity 2104 may have an opening at the bottom part of fin 2100. According to some embodiments apparatus 2106 may be inserted into cavity 2104 to close off fin 2100 from the bottom.

In some demonstrative embodiments, apparatus 2106 may include at least one lever 2108, adapted to be positioned in at least two different positions. For example, as demonstrated in FIG. 21, lever 2108 may be positioned at a first position, wherein fin 2100 may be rigid, e.g., when fin 2100 cannot be bent more than 10 degrees, preferably, no more than 5 degrees.

According to some demonstrative embodiments, lever 2108 may be positioned at a second position, wherein fin 2100 may be flexible, e.g., when fin 2100 can be bent more than 10 degrees, preferably, more than 15 degrees, more preferably, more than 20 degrees. This is exemplified in FIG. 22, as described in detail below.

According to some embodiments, fin 2100 may be made of a single material, e.g., as explained in detail hereinabove. According to other embodiments, fin 2100 may be comprised of at least two different sections, wherein each section may be made of a different material. For example, fin 2100 may include an upper section 2102 which may be made of a material which is more rigid or more flexible than the material of fin 2100. According to some embodiments, including at least two different sections of the fin having different degrees of rigidity may enable the fin to have different degrees of “grasp” of in waters.

Reference is now made to FIG. 22, which illustrates exemplary adjustably flexible fin 2100. FIG. 22A illustrates a side view of the exemplary adjustably flexible fin 2100 and FIG. 22B is an isometric view of exemplary adjustably flexible fin 2100.

As explained above, according to some demonstrative embodiments, fin 2100 may include a cavity 2104, for example in the base portion of fin 2100.

According to some embodiments, cavity 2104 may have an opening at the bottom part of fin 2100. According to some embodiments apparatus 2106 may be inserted into cavity 2104 to close off fin 2100 from the bottom.

In some demonstrative embodiments, apparatus 2106 may include at least one lever 2108, adapted to be positioned in at least two different positions. For example, as demonstrated in FIG. 22, lever 2108 may be positioned at a second position, wherein fin 2100 may be more flexible in comparison to to a situation in which lever 2108 is at the first position, e.g., as demonstrated in FIG. 21.

According to some demonstrative embodiments, lever 2108 may be positioned at various positions between the first and second position, thereby providing for different degrees of flexibility to fin 2100. For example, a user of fin 2100 may alter the flexibility of fin 2100 by adjusting the position of lever 2108 of apparatus 2106. When the user of fin 2100 moves lever 2108 to be at a first position, e.g., as depicted in FIG. 22, fin 2100 will be at the outmost rigid form and may be especially useful in case of surfing in high waves (enabling the user to have a better “grip” in the waters.

According to another example, when the user of fin 2100 moves lever 2108 to be at a second position, e.g., as depicted in FIG. 21, fin 2100 will be at the outmost flexible form and may be especially useful in case of surfing in low waves (enabling the user to have more “freedom of movement” in the waters).

For intermediate level waves, the user may adjust the position lever 2108 to be at a position in-between the first and second position.

Reference is now made to FIG. 23, which illustrates a side view of apparatus 2106 in accordance with some demonstrative embodiments described herein.

FIG. 23A illustrates apparatus 2106 in a first position (also referred to as a “closed position” or “horizontal position” or “first horizontal position”), wherein lever 2108 is resting on a body 2304 of apparatus 2106.

FIG. 23B illustrates apparatus 2106 in a second position (also referred to as an “open position” or “vertical position” or “second vertical position”), wherein lever 2108 is detached from body 2304 of apparatus 2106.

As explained hereinabove with respect to FIGS. 21 and 22 a user of a fin, e.g., fin 2100, may change the position of lever 2108 and adjust the flexibility of fin 2100 in accordance with sea condition and/or height of the waves.

According to some demonstrative embodiments, base 2304 may be made of any suitable material to enable the firm positioning of fin 2100 into a surf board including, for example, polyurethane, polystyrene foam, fiberglass, polyester, epoxy resin, kevlar fiber, carbon fibers, silicones, rubber, wood, plastic, metal, aluminum and the like or any combination thereof.

In some demonstrative embodiments, apparatus 2106 may include hinge 2306 to act as an axis point between lever 2108 and body 2304. According to some embodiments, when a user of fin 2100 wishes to alter the position of lever 2108 the user may cause the rotation of hinge 2306, for example, by using a designated wrench or key.

According to some demonstrative embodiments, in order to rotate hinge 2306, a user may use ring 1800 (FIGS. 18-20).

While this invention has been described in terms of some specific examples, many modifications and variations are possible. It is therefore understood that within the scope of the appended claims, the invention may be realized otherwise than as specifically described. 

1. An apparatus for adjusting the flexibility of a fin of a waterborne vessel comprising at least one movable and/or rotatable component adapted to be positioned in one of at least two different positions, a first position and a second position, wherein when said component is positioned at said first position, said fin exhibits a first degree of flexibility, and when said component is positioned at said second position, said fin exhibits a second degree of flexibility, wherein said first degree of flexibility is greater then said second degree of flexibility.
 2. The apparatus of claim 1, wherein said waterborne vessel is selected from the group consisting of: surfboard; kitesurf board; windsurf board; boogie board; paddle board; wave board; wake board; kayak; canoe; sailing boat; waterski, jetski.
 3. The apparatus of claim 1, wherein said component comprises a disc comprising a plurality of rods and a plurality of slots; a screwing element; and wherein said disc may be rotated to various positions and reversibly locked in place via said plurality of slots and wherein rotating said disc to various positions provides a different degree of flexibility to said fin.
 4. The apparatus of claim 3, having means for rotating said disc by hand.
 5. The apparatus of claim 4 having means for rotating said disc by means of a screw driver.
 6. The apparatus of claim 1, wherein said component comprises a movable lever adapted to be positioned in one of at least two different positions, a first horizontal position and a second vertical position, wherein when said component is positioned at said first horizontal position, said fin exhibits a first degree of flexibility, and when said component is positioned at said second vertical position, said fin exhibits a second degree of flexibility, wherein said first degree of flexibility is greater then said second degree of flexibility
 7. A wearable adjustment device adapted to enable the rotation of a disc contained within a fin and to provide a different degree of flexibility to said fin.
 8. The device of claim 7, wherein said waterborne vessel is selected from the group consisting of: surfboard; kitesurf board; windsurf board; boogie board; paddle board; wave board; wake board; kayak; canoe; sailing boat; waterski, jetski.
 9. The wearable adjustment device of claim 8, wherein said device is a ring. 